I saw some YouTube videos about an aftermarket "plus four" follower for the GSG magazines. One video that I watched gave them a thumbs down.
I have five magazines for my GSG 1911-22 and I have installed the plus-4 follow in each of those magazines. They work great for me but I can see how some folks might not care quite as much for their use as I do. Simply put, it's not a flawless upgrade.
--you lose the finger button for the follower with the +4 follower. The follower does have a hole in it and there is a thumb-piece tool that you can buy to assist in loading them. This is another piece to buy and you have to use the tool each time, so it's more work to load than the original mag with standard 10-rd follower
--you also cannot use the loading tool for the first 2-3 rounds when loading the mag, you actually thumb the slide lock cutout on the follower itself until the hole appears to insert the tool. It's another work around that seems to annoy people
--sometimes I'll see that my upgraded follower doesn't want to lock the slide back on the last shot... and sometimes, the follower itself actually holds the slide back rather than actuating the slide lock -- and what you end up with is a mag that doesn't drop free with the push of a button, you must draw the slide rearward for it to fall free. Again, it's sporadic and it is a work-around if you want the +4 option
None of those are dealbreakers for me. If it were only +1 on each mag, it certainly would seem like a hassle, but 4 extra rounds is quite an upgrade in my opinion, and since I only run the pistol for fun shooting at empty 12ga hulls, I love the +4 even if I have to fiddle here and there.
The magazine body and construction is very good, the true annoyance here are the idiot states that limit magazine capacity, making it FAR easier for any/every rimfire semi-auto handgun builder to simply design their pistols around a 10-rd magazine just so it's logistically easier to sell all around the nation. In other words, if not for the silly states, this pistol likely would have been designed around a 12-14 round capacity in the first place, I think.